Some present may remember an entertaining (not to mention illuminating (pun intended) ) blog by Professor Larry Moran:
I am a high school Biology teacher and Professor Moran threw out some challenges which cut me to the quick.
Here is a very brief and incomplete summary:
The dual photosystems of Blue-Green Algae clearly evolved late from a combination of a type I reaction center in species like Heliobacter and green sulfur bacteria and a type II reaction center from species like purple bacteria and green filamentous bacteria. The oxygen evolving complex was a late addition.
Both photosystems employ Porphyrins and Carotenoids which are important in various metabolic processes (not just photosynthesis) meaning their evolutionary history may reflect many other functions only to be co-opted later for photosynthesis. Meanwhile both can be demonstrated to have abiogenic origins.
Meanwhile RuBisCO is found in non-photosynthetic species…
According to Professor Moran, many misconceptions are perpetuated when teaching according to textbook orthodoxy. Instead we should consider Photoreduction and Photophosphorylation as two stand-alone processes, and that the capture of light energy to produce carbohydrates is a highly specialized phenomenon; which, from an evolutionary point of view is not really (at least not originally) part of “photosynthesis” (i.e. carbohydrate anabolism).
Even Flowering Plants not only can, but in fact most of the time do, decouple ATP/NADPH production from Carbon fixation. Indeed, much of the ATP & NADPH generated by Photosystems II & I respectively are in fact redirected to immediate energy needs, even in flowering plants.
Meanwhile, I heartily agree with Larry Moran’s thesis that it is important (nay, let’s say instead imperative) to teach students that there’s more to life than just flowering plants and humans?
Larry Moran (in very unsubtle and less than gentle terms) “suggests” such strategies should apply to teaching of all biochemistry; i.e. from simple pathways to more complex pathways.
A recent “must-read” article inspired me to respond to Larry Moran’s challenge,
… and I have cobbled together a worksheet, where I attempt to prove that photosynthesis is
1 – misunderstood (tis not really about Glucose and it’s not even about the Calvin Cycle) at least from a Biochemist’s evolutionary POV. Ecologists have justification to differ.
2 – NOT “irreducibly complex” but rather a hodge-podge cobbling by evolution over a long period of time. (cf https://embryo.asu.edu/pages/evolution-and-tinkering-1977-francois-jacob)
Larry Moran’s fingerprints are all over this work of mine, for which I really cannot claim any originality on my part.
I would be grateful for any constructive input and suggestions for improvement. Remember, the intended target audience remains high school students.
Thanks in advance and best regards,
Here it is:
Who is “Bill”?
Well, technically, neither are Darwin’s Finches… Chimp’s differences from humans are around in the same ballpark as the Galapagos’ Finches. OK OK… compared to the Finches, the LCA in the Hominids were a little further back in time albeit with evident interbreeding between chimps and humans even after the initial split.
Why is colewd here alone all by himself?
“Eli Eli lama sabachthani?”
Statistical confidence levels differentiate empirical conclusions? If we had to estimate a confidence level that general relativity can predict how light would be deflected by a mass like the sun we would have greater then 95% confidence in our conclusion.
What would our confidence be of random mutation and natural selection from cell division producing a spliceosome?
Why can’t we quantify this? Are all empirical conclusions really the same?
Can you support this claim?
colewd = William D. Cole = Bill.
Is that what you teach your students? You could be fired for that.
Uhmmm… OK, I’ll bite.
Why would that be now?
Poe’s Law again!!!
You are joking right?
According your logic, it was staitustically impossible for my wife and Myself to have met and married, but there you have it.
I remember your participation on the sandwalk.blogspot when I questioned your sincerity in having an honest exchange of ideas
Then as now I doubted your earnestness when I realized your sophist ulterior motives
The only reason I have lingered so long on this thread is due to the abundance of dissimultude you and your confreres are spewing in response to the cogent rebuttals of your detractors
I remain grateful and will rewrite my worksheet in anticipation of the ID Taqiya prolgated by creationist jihadi outside my classroom
This is not what I am saying. There are differences in hypothesis strength based on the certainty that cause has been isolated.
You tell your students that “irreducible complexity” is not a problem for evolution. On what knowledge do you base this assertion.
Can you describe how an irreducibly complex molecular system evolved? What mechanism(s) do you ascribe to this event. How do you ascribe statistical confidence that those mechanisms are indeed the cause.
Again, what is the basis of knowledge that your claim is true?
No, the problem is that you are repeating Behe’s error. You’re focusing on whether particular systems are IC or not. It’s right there in the thread title: A worksheet targeted for High School students proving once and for all that Photosynthesis is not “Irreducibly Complex”.
Whether there are IC systems in biology is not the issue. There are such systems. Whether they are evolvable is the issue.
You should be teaching your students that biological IC systems are evolvable, not trying to demonstrate that they aren’t IC.
Now that your initial panic has subsided, do you recognize that Behe accepts common descent, including the fact that humans and chimpanzees share a common ancestor?
Urgh. Worth a mention though that statistical confidence, and the 95% threshold, originate with Ronald Fisher, a noted evolutionist and one of the architects of the Modern (sic) Synthesis.
Or that most of the groundwork for statistical analysis was laid down by early geneticists like Galton, Pearson and, indeed, Fisher.
What would be our confidence of nested hierarchies coming from evolutionary processes?
What would be our confidence of nested hierarchies coming from design processes?
What would be our confidence in, say, 2 billion BC, of Hawaii appearing in the middle of the Pacific Ocean by now (involves plate tectonics)? Of course things depending heavily upon contingencies aren’t exactly predictable, while the differentiation of the crust from the mantle is more or less predictable from plate tectonics.
OK – now I see where you are coming from.
You and I and Bill are in agreement that I knocked down a strawman argument posed by Otangelo Grasso because photosynthesis is not IC as apparently Behe himself concedes and I also point out in the OP and on many occasions in the thread.
You are correct, the title is unfortunate and should be changed.
I note that Bill has torn a page from Behe’s hymnal and resorted to the identical example that Behe employs: where a complex system can be cobbled together by Natural Selection but individual components are themselves too complex to arise by Natural Selection and are therefore candidates for IC. You will note I referred to that tactic as “moving the goal posts”.
The specific example Bill borrowed from Behe was the bacterial flagellum. Of course, that particular Shibboleth is easily slain.
So I agree the title of my OP was unfortunate. I would appreciate if you could point out any suggestions for improvement in the worksheet itself.
Did you even read the worksheet about the obligatorily mutualistic metabolism of two modern Lithotrophs?
As mentioned on previous occasion, I have had qualms about the raison d’être of this site.
It has been hijacked by sophists to promulgate dissimilitude; not on the site, but elsewhere.
Typically, what occurs here is a “safe quarantine” from a creationist’s POV to pose objections to Evolution. Ever more sophisticated and detailed rebuttals to continuing creationist objections are gladly received, twisted out of context and misrepresented elsewhere.
Creationists thereby create the illusion they have successfully addressed their opponents’ arguments and obstinately pretend the creationist thesis remains cogent.
Participation on this site is tantamount to aiding and abetting the enemy!
“Enemy”? The enemies of truth – the casuistic creationist sophists – twisters of words and context contortionists who engage in Taqiyya in cyber-creationist-madrassa
Enough! Forewarned is forearmed! I decided to turn the tables and adopt their own tactics by inviting objections to my worksheet in order to better anticipate the falsehoods spewed outside the classroom.
I note with bemusement that they have cottoned on to my strategy and remained obtusely silent. Poor Bill stands alone.
I can only surmise, there remain no further objections to my worksheet and that its thesis remains standing.
Would that be correct Sal? … Mung?
In that case, à la prochaine…
Haha, yea right.
By saying, it evolved!
Great education our kids are getting.
Yes, both with experimental and wild-type observations.
I specifically mentioned the case of a neutral potentiating mutation, that has to happen first, in order for a later mutation to be beneficial due to an epistatic interaction with the neutral one. That is a concrete example of an irreducibly complex function which require both mutations for the function.
I happen to know just off the top of my head, two examples of those. One is chloroquine resistance in Plasmodium falciparum. This resistance requires several successive mutations to evolve, and at least one of them has to be a neutral mutation that happens first, in order for later mutation to become beneficial in conjunction with the neutral one. Without the neutral mutation, the beneficial one won’t be beneficial but either neutral or deleterious, and so chloroquine resistance won’t evolve. So the chloroquine resistance function is irreducibly complex as it takes multiple mutations in combination, and if they are missing you won’t get resistance.
Yes, the Cit+ mutant strain which can metabolize citrate under aerobic conditions, is irreducibly complex. Because it takes at least one if not several potentiating, neutral or beneficial background mutations to happen first, in conjunction with the duplication into the operon active under aerobic conditions. And without these background mutations, the epistatic interactions are not in effect and then aerobic citrate transporter activity fails.
So it’s irreducibly complex and it evolved.
Those are just two examples I know by memory. There are many many known cases of functions emerging due to epistasis.
But even if there were no other cases known, all it takes is a single example to show that Irreducible Complexity is not a barrier to evolution. It empirically demonstrates in the most direct way possible, that a structure or function being Irreducibly Complex, can not suffice as an argument against the possibility of it evolving.
IC is bunk and it always was.
Careful now… as Keiths is correct to point out, we must parse our terms carefully and be careful what is meant by the term “Irreducibly Complex”
According to Behe’s nuanced definition, IC is
Part 1: “a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning”,
Part 2: and argues that since “an irreducibly complex system that is missing a part is by definition nonfunctional” it could not have evolved GRADUALLY through natural selection.
Does Irreducible Complexity exist according to Part 1 of Behe’s definition? Yes! Of course, photosynthesis would not be an exemplar, explaining why colewd and Grasso needed to “move the goal posts”.
Is Part 2 of Behe’s definition correct? No! Natural Selection can result in complex systems which are IC, as John Harshman eloquently elucidated. Simply put: Irreducible Complexity is “evolvable”, explaining why colewd is resorting to “statistics rebutals” by conflating of what a layman’s fuzzy understanding “most likely probable” actually means in mathematical and scientific terms as opposed to what is “most likely plausible” according to the evidence examined. In layman terms: often the least likely is in fact the most plausible, not to mention most obvious.
Check out this earlier exchange:
The bacterial flagellum – is “evolvable” . A high school student could trace the connections with ATP Synthase and its commonalities with a DNA helicase with ATPase activity and H+ motors of Flagella
check out https://en.wikipedia.org/wiki/ATP_synthase#Evolution
Thank you… I will file this away for future reference. I am in your debt.
Yes, and I think it is good work. What now matters is what level of claim does it support. Can you derive a viable mechanism for the data? How would a creationist challenge it? The key is matching the claim with the evidence and being on solid ground when you are challenged.
Irreducible complexity is not a problem for evolution. I think this claim will bite you in the ass.
And yet, in your worksheet, you fail to do so. What gives?
Walk us through this. You created a worksheet to help your students work out that photosynthesis is not IC?
Changed to what?
A worksheet targeted for High School students proving once and for all that Photosynthesis was never “Irreducibly Complex”
Take out the part claiming cells are merely chemical reaction chambers. Take out the claim that proto-cells can be found at deep sea thermal vents. Tell us what point you’re trying to make to your students.
Would you care to explain?
There are two parts to Behe’s definition ( other writers seem to have different versions)
My worksheet passes muster on both counts.
If you disagree, point out where exactly the exercise fails to hit target
We just cross-posted
Perhaps you should read the title of the worksheet first before levelling your criticisms
I think this post has got to be the most eloquent rebuttal to Bill’s objections regarding boiler-plate creationist challenges to my worksheet.
Mung take note
I can’t find that claim anywhere.
What do you think the following is referring to:
Conditions in the early ocean? The give-aways are “the early ocean” and “primordial seawater”. I don’t think he’s claiming iron-sulphur bubbles in general are necessarily proto-cells wherever they exist. At worst he needs to clarify that.
The conditions then were different than now… a reducing atmosphere for one example
Of course I would expect my students to understand that those Iron-Sulfur bubbles were necessary but not sufficient for abiotic proto-cells
Necessary clarification already is provided in the link immediately preceding the bit Mung quotes
ITMT, Nick Lane and others are attempting to recreate alkaline hydrothermal vent incubators in the lab, to support the thesis explained in my worksheet, which addresses some of Bill’s more pertinent objections
I remain perplexed by Mung’s objections to the suggestion that a living cell is nothing more than a biochemical reaction chamber, where reactions are coordinated by enzymes.
What alternative does he propose?
Some version of “Vitalism”?
Mung should correct me if I am wrong, but I believe that is correct. If I understand him correctly he is sympathetic to the idea that all living things are driven by some internal desire or intent.
We went down that particular rabbit hole here.
Cells are capable of coordinating complex activities like cell division, transcription translation, alternative splicing, DNA repair, and cell differentiation. All these process are very complex and go well beyond the description of biochemical reactions. The cell also operates from genetic information in the form of DNA.
Your descriptions don’t address the issue of the origin of new DNA sequences either in the case of OOL and the origin of photosynthesis. An educated creationist will push you on this. The more irreducibly complex the system the longer the DNA sequences that are required to explain their origin. The number of ways to arrange proteins goes up exponentially with the addition of every additional amino acid.
Yea, just like the human brain. Just a bag of chemicals.
“The H+motor of the FO particle shows great functional similarity to the H+
motors that drive flagella. Both feature a ring of many small alpha-helical proteins that rotate relative to nearby stationary proteins, using a H+
potential gradient as an energy source. This link is tenuous, however, as the overall structure of flagellar motors is far more complex than that of the FO particle and the ring with about 30 rotating proteins is far larger than the 10, 11, or 14 helical proteins in the FO complex.”
Every part Tom, every stinking part, caused by some new mutation, which causes some reproductive success, happening in exactly the right place at the right time! THAT IS THE CHALLENGE OF DEBUNKING IC!
Not just saying, well, look here is some similarity…. Where did the L-Ring come from, where did the stators come from, where did the P-Ring come from, how did they get where they are, when did the hook develop, before or after the filament? What was its reproductive advantage?
Now I see why you think IC is so easy to overcome, you don’t get the problem.
Here we go again with this nonsense. Unbelievable
… oh wow!
Even Kepler gave up the idea that planets were pushed in elliptical al orbits by Angels!
Uhmmm … you should revisit some of the previous posts.
Even … scratch that… ESPECIALLY Behe would affirm that YOU don’t get the problem
I feel your pain!
This is like a pathetic rerun of the movie Ground Hog Day!
It is really difficult for me to wrap my head around Ignorachio elenchi ad infinitum
I cannot anticipate the dissimultudes pounded into my students craniums outside the classroom. That is why I am obliged to drop my nets here despite the unpleasant odour.
Some of material is excellent
Mung has yet again inspired another worksheet … together with Bill’s impromptu assistance
I remain grateful to all participants so far
I am curious
How would you respond to Rumraket’s succinct and eloquent response to Bill?
The curious thing about the flagellum is that, although the numerous proteins don’t have much resemblance to proteins outside the flagellum, they do have much in common with each other. It’s as if one sequence gave rise to all the others. Or, some designer kept sticking his thumb into the same corner of protein space and kept pulling out plums (in order to make diseases!).
Well, duh, of course they’re all similar. With such a huge sequence space it must have taken the designer an almost infinite amount of time to find the right sequence for a flagellum protein. He just tweaked that one to build the rest so he could move on to designing talking snakes A.S.A.P.
If only he could have used the rib of some other organism, that would have made his life so much easier
What are the functioning “parts” of chloroquine resistance? What is their function?
I mean that is just such a pandas thumb bullshit talking point, and that’s your BEST example of irreducible complexity? Being born with no legs also keeps you from getting frostbite on your toes, is that another example?
When evolutionists start trying to pull out this shit, then I know for sure they have nothing.
Could you summon one for us?
In the meantime, I’m still interested in your response to this:
There is no explanation available from the well at this point 🙂
You write carefully keiths and you are smart so why did you put the term “fact” to describe an untested hypothesis. You worked in industry do you have any experience with the scientific method?
There are some severe issues with this untested hypothesis including gene expression and alternative splicing patterns that cannot be explained by inheritance. When I mentioned this to Mike he said that I might be right but he had very little interest in this hypothesis. I published the conversation for you to review.
Here we go again with this nonsense. Unbelievable
Easier to debunk that way.
It’s nonsensical. It’s propaganda. It’s a philosophical claim posing as a scientific claim. It’s a proclamation of fact without any factual support. It’s you, preaching, rather than teaching.
Why not let your students decide whether the cell is “nothing more than a chemical reaction chamber” instead of telling them what to think?